JP2008201925A - Method for incinerating carbon attached to carbonization chamber of coke oven - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for incinerating the carbon attached to a carbonization chamber of a coke oven, which enables optimum incineration of carbon for reducing extrusion resistance. <P>SOLUTION: When carbon attached within a coke oven carbonization chamber 3 is removed by incineration while injecting a gas containing oxygen from an injection nozzle 2, the O<SB>2</SB>concentration of a flue gas during incineration is measured, to find an O<SB>2</SB>concentration X at which the extrusion resistance value will be the minimum, based on the correlation between the CO<SB>2</SB>concentration and the extrusion resistance value in the next extrusion. After the incineration of carbon is initiated, when the O<SB>2</SB>concentration of the flue gas is increased to X after the content is decreased to less than X, the incineration of carbon is stopped. By the method, the oven walls can be made on which carbon is smoothly attached. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for removing carbon adhering in a coke oven carbonization chamber by incineration while inserting an injection nozzle into the carbonization chamber and injecting a gas containing oxygen.

  In the coke oven carbonization chamber, carbon generated by pyrolysis of the dry distillation product gas and pulverized coal scattered at the time of charging the coal adhere to the furnace wall and coke, thereby generating carbon attached to the furnace wall. As the carbon attached to the furnace wall grows on the furnace wall surface, it lowers the thermal conductivity of the furnace wall and reduces the effective volume of the carbonization chamber, thereby reducing the productivity of the coke oven. Furthermore, since it causes so-called clogging, which makes it impossible to extrude coke from the carbonization chamber, periodic removal work is necessary.

The following two methods are well known as methods for removing the carbon deposited in the carbonization chamber.
(A) A method in which the tip is sharply sharpened and manually pushed down using a 4 to 5 m long jig.
(B) A method in which one or both of the coke extrusion furnace lids and the gas riser pipe are opened, and air is introduced from the furnace lid portion into the carbonization chamber by natural draft to burn the carbonization chamber-attached carbon.

  However, in the removal method by mechanical action as in (a), the carbon layer is completely peeled off from the furnace wall, so that the sealing function of the joint portion by carbon is impaired. In addition, 3 to 4 workers have to spend 15 minutes or more, and there is a problem that forced labor is required in a bad environment due to high heat and dust.

  In the method (b), the furnace wall in the vicinity of the air introduction part is initially incinerated and removed by carbon, but after that, cold air passes through that part and receives excessive overcooling locally. Damages due to brick spalling and adverse effects such as joint opening will occur. Also, the air used for combustion is about a fraction of that entering the carbonization chamber, and most of the air is discharged outside the furnace without being involved in combustion, so the amount of carbon combustion must be increased. I can't. For this reason, a long time is required for the carbon removal work, and production is hindered.

  In order to solve these problems, a method has been developed in which an injection nozzle is inserted into the carbonization chamber to inject a gas containing oxygen to burn and remove the attached carbon. In this method, it is necessary to control the gas blowing conditions. Patent Document 1 describes a method for determining the gas injection conditions by grasping the total amount of carbon adhering from the extrusion current value of a coke extruder that extrudes coke from a carbonization chamber. Is disclosed. In this method, the relationship between the extrusion current value and the amount of adhering carbon is obtained in advance, and when the extruding current value is high, it is determined that the carbon adhesion is large and incineration is strengthened.

However, the extrusion current value may not necessarily reflect the carbon adhesion amount. For example, when the extrusion current value increases due to the presence of an undried portion due to insufficient carbonization time, the extrusion current value does not indicate the amount of carbon adhered. Further, in the furnace wall having a large recess due to a brick defect or the like, the extrusion current value increases even if no carbon is attached. Thus, even if the extrusion current value is high, it may not be said that the carbon adhesion amount is large. Moreover, since the relationship between the carbon adhesion amount and the extrusion current value varies depending on the state of the wall surface of each carbonization chamber, it is necessary to obtain this relationship for each carbonization chamber in order to carry out the method of Patent Document 1. A large amount of data storage is required.
JP-A-61-231085

  The present invention solves the above-mentioned conventional problems, does not impair the sealing function of the brick joints, does not cause damage such as spalling, and also hinders work and productivity in adverse environments. There is also provided a method for incinerating carbon deposited in a coke oven carbonization chamber capable of appropriate carbon incineration to reduce extrusion resistance without requiring a large amount of data accumulation even when there is a brick defect or the like on the furnace wall. It is for the purpose.

The present invention made to solve the above problems is a method for removing carbon adhering to a carbonization chamber of a coke oven by incineration while injecting a gas containing oxygen from an injection nozzle inserted into the carbonization chamber. The O ₂ concentration X at which the extrusion resistance value is minimized is obtained from the correlation between the O ₂ concentration of the combustion exhaust gas and the extrusion resistance value at the next extrusion, and after the start of carbon incineration, the O ₂ concentration of the combustion exhaust gas is X The carbon incineration is stopped when it is lowered to less than X and then raised to X. In practice, it is preferable that the O ₂ concentration X at which the extrusion resistance value is minimized be corrected and used in consideration of the distance from the sampling position to the O ₂ concentration meter.

  According to the present invention, it is possible to appropriately control the incineration of carbon that adheres to and grows on the wall surface in the coke oven carbonization chamber, smoothing is possible even on the wall surface of the carbonization chamber where there is a recess, and the extrusion resistance It can be minimized. In this case, since the sealing function of the brick joints by carbon is not impaired, the extrusion resistance can be reduced while avoiding leakage of generated gas and weakening of the carbonization chamber furnace wall.

  In FIG. 1, 1 is a blower for carbon incineration air, 2 is an injection nozzle for carbon incineration air, and 3 is a coke oven carbonization chamber. Carbon adheres and grows in the carbonization chamber due to coal charging, carbonization, and carbonization. In order to incinerate and remove this carbon, the injection nozzle 2 is inserted every time coke extrusion is completed from the coke oven carbonization chamber 3, and carbon incineration air is injected. As a result, the adhering carbon burns and the exhaust gas is discharged from the riser 4. Although air is used here for incineration, it is not necessarily limited to air as long as it contains oxygen.

  If the carbon adhering to the furnace wall of the coke oven carbonization chamber 3 grows excessively and forms a bump, the extrusion resistance increases. However, excessive incineration not only impairs the sealing function of the brick joints, but also may increase the extrusion resistance by exposing the unevenness of the wall surface. Therefore, it is important to properly incinerate while properly controlling the carbon adhesion amount.

In the present invention, incineration is controlled by paying attention to the O ₂ concentration of combustion exhaust gas when injecting a gas containing oxygen from the injection nozzle 2 to burn carbon. For this reason, as shown in FIG. 1, the flue gas sampled from the riser 4 and other flue gas passages is sent to the O ₂ concentration meter 5 to continuously measure the O ₂ concentration in the flue gas.

The O ₂ concentration in the combustion exhaust gas is considered to be an indicator of the smoothness of carbon adhering to the furnace wall, not just an indicator of the amount of carbon attached. That is, in the coke oven carbonization chamber 3 with a remarkable furnace wall recess, the carbon in the recess grows preferentially. This is because the furnace wall of the recess has the highest temperature because of its high thermal conductivity, and the carbon is difficult to peel off during the extrusion operation. Since carbon adhering to such a furnace wall recess is less efficient in burning by the injected gas, even if adhering in a large amount, it does not contribute much to the decrease in O ₂ concentration. On the other hand, the bump-like carbon that grows on the smooth part of the furnace wall has high combustion efficiency, so that the O ₂ concentration is remarkably reduced even with a small amount. Therefore, it is possible to estimate the smoothness of the coke oven carbonization chamber 3 by measuring the O ₂ concentration of the combustion exhaust gas.

When the injection nozzle 2 is inserted into the coke oven carbonization chamber 3 and a gas containing oxygen is injected, carbon that has grown thinly in a petal shape or carbon that has grown in a convex shape burns. Since these have high combustion efficiency, as shown in the graph of FIG. 2, the O ₂ concentration in the combustion exhaust gas greatly decreases immediately after the start of carbon incineration. Thereafter, as incineration of petal-like carbon and convex carbon is completed, the O ₂ concentration in the combustion exhaust gas begins to rise.

FIG. 3 is a graph showing the relationship between the O ₂ concentration and the extrusion current value at the next extrusion, and it can be seen that the extrusion current value is minimized when the O ₂ concentration is 14% under the measurement conditions in this case. This extrusion current value represents the extrusion resistance value. From the correlation between the O ₂ concentration in the flue gas as shown in the graph of FIG. 3 and the extrusion resistance value at the next extrusion, an O ₂ concentration X at which the extrusion resistance value is minimized is obtained.

  X is 14% here, but it is not necessarily 14% depending on the type of injection nozzle 2, the type of gas to be injected, the type of coke oven, and the like. However, since it is constant when the same injection nozzle 2 and the same gas are used in the same coke oven, there is no need to separately obtain data for each carbonization chamber as in the prior art.

In the present invention, the O ₂ concentration X at which the extrusion resistance value obtained in this way is minimized is used, and after the start of carbon incineration, the O ₂ concentration of the combustion exhaust gas decreases to less than X, and then reaches X again. Stop carbon incineration when rising. As a result, the wall surface is kept almost smooth by the carbon, and the resistance during the next extrusion after charging the coal can be reduced. In practice, it is preferable to use the O ₂ concentration X at which the extrusion resistance value is minimized by correcting the O ₂ concentration X in consideration of the distance to the O ₂ concentration meter as shown in the examples.

If the carbon adhesion in the coke oven carbonization chamber 3 is too small, the O ₂ concentration of the combustion exhaust gas may not become less than X even if the carbon incineration is started. In preparation for such a case, it is preferable to program so as to “stop carbon incineration when the O ₂ concentration of the combustion exhaust gas does not become less than X even after incineration for a predetermined time”. The “predetermined time” in this case is individually set according to the characteristics of the incinerator.

In addition, when petal-like carbon or convex carbon is growing excessively, even if incineration is carried out for a considerable period of time, the O ₂ concentration does not rise to X, and as a result, incineration is carried out for a long time that hinders productivity. It is assumed that the situation will continue. In preparation for such a case, it is preferable to program so as to “stop carbon incineration when the O ₂ concentration of the combustion exhaust gas does not rise to X even after incineration for a predetermined time”. The “predetermined time” in this case is also set individually depending on the characteristics of the incinerator.

As described above, according to the present invention, it is possible to perform an appropriate carbon incineration for reducing the extrusion resistance using the O ₂ concentration of the combustion exhaust gas as an index. For this reason, damage, such as spalling, is not caused without impairing the sealing function of the brick joint. In addition, work in a bad environment is not necessary, and optimal carbon incineration is possible even when there is a brick defect in the furnace wall. In addition, a large amount of data storage for each carbonization chamber is not required.
Examples of the present invention are shown below.

For a coke oven, the relationship between the O ₂ concentration in the flue gas and the extrusion current value at the next extrusion was obtained, and the results shown in Fig. 3 were obtained. The extrusion resistance value is minimized when the O ₂ concentration is about 14%, but the actual equipment has a distance from the gas sampling point to the O ₂ concentration meter, so the measured O ₂ concentration is about The gas discharged 10 seconds ago. For this reason, in operation, when the O ₂ concentration becomes 13.5%, a signal to stop the blower that sends gas to the injection nozzle 2 is output. As described above, it is preferable that the optimum concentration X is corrected to be slightly lower, but the correction range is appropriately set according to the characteristics of the gas sampling device.

In this example, “If the O ₂ concentration is 13.5% or more after 30 seconds from the start of carbon incineration, the carbon incineration is stopped at that time” and “O ₂ concentration after 150 seconds from the start of carbon incineration” If it is less than 13.5%, the carbon incineration is stopped at that time ”. For this reason, in all the carbonization chambers, carbon incineration is performed for a minimum of 30 seconds and a maximum of 150 seconds.

  FIG. 4 shows the transition of the extrusion current value when the present invention is carried out continuously for one month. By adopting the present invention, the extrusion current value began to decrease as compared with the past, and it decreased by 15% in about one month. Until then, there was no carbon adhesion on the wall surface, and the recess of the carbonization chamber furnace wall was exposed, whereas the carbonization chamber furnace wall after about one month from the start of implementation of the present invention was smooth. Carbon was attached, and the concave portion was covered and hidden. That is, the reason why the extrusion current value decreased as shown in FIG. 4 was not because carbon intensification was strengthened, but the petal-like or convex carbon was incinerated while growing the carbon in the furnace wall recess. This is because the furnace wall was smoothed.

It is sectional drawing which shows embodiment of this invention. It is a graph showing changes of the O ₂ concentration in the combustion exhaust gas during the carbon burning. Is a graph showing the relationship between the O ₂ concentration and extruding the current value in the embodiment. It is a graph which shows transition of the extrusion electric current value in an Example.

Explanation of symbols

1 blowing blower 2 injection nozzle 3 coke oven carbonization chamber 4 riser 5 O ₂ concentration meter

Claims (2)

The carbon attached to carbonization chamber of coke oven, there is provided a method of removing incinerated while injecting a gas containing oxygen from the injection nozzle inserted into the carbon reduction chamber, when the O ₂ concentration and the next extrusion of the flue gas When the O ₂ concentration X when the extrusion resistance value becomes the minimum is obtained from the correlation with the extrusion resistance value, and after the start of carbon incineration, the O ₂ concentration of the combustion exhaust gas decreases to less than X and then increases to X Coke oven carbonization chamber adhering carbon incineration method, characterized in that carbon incineration is stopped. _{2. The} method for incinerating carbon deposited in a coke oven carbonization chamber according to claim 1, wherein the O ₂ concentration X at which the extrusion resistance value is minimized is corrected in consideration of the distance to the O ₂ concentration meter.

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